Acalculia, or dyscalculia, is the loss or impairment of previously acquired arithmetic skills, which in the majority of cases is due to damage to cortical centers, particularly in the left hemisphere of the brain. Accordingly, acalculia should be distinguished from dyscalculia, which is usually diagnosed as a specific developmental disorder during infancy or school age.
What is dyscalculia?
Acalculia (dyscalculia) is an acquired impairment in dealing with arithmetic quantities (arithmetic operations, number handling) caused by damage in the cortical centers of the brain, usually the left hemisphere (half of the brain). While the other intelligence is not impaired, an acalculia can manifest itself in everyday life, among other things, by difficulties in dealing with money, telephone numbers and/or telling the time, in estimating distances, price discounts or quantities, and by impairments in processing arithmetic symbols. Depending on the severity of the underlying lesion, heterogeneous forms of dyscalculia may manifest. While in some only complex arithmetic operations are impaired, in others affected by acalculia, elementary basic arithmetic operations such as addition or subtraction of single-digit numbers may be impaired.
Causes
Primary acalculia, which occurs rather rarely, may be caused by damage to the language-dominant cortex as a result of an insult (stroke). The impairment known as secondary acalculia, on the other hand, is more common and may be associated with a reduction in brain performance due to memory impairment, attention deficits, and a marked tendency to perseverate (pathologically persist or dwell on a thought or linguistic utterance). Acalculia is also associated with damage to the parietal and temporal lobes in agraphia and finger-foot-toe diagnosis. Furthermore, acalculia occurs as a symptom of Gerstmann syndrome (also angularis syndrome), which is additionally manifested by agraphia, finger aagnosia, right-left disturbance, and in which the left angular gyrus is usually affected. Since arithmetic operations are partially controlled by linguistic functions, acalculia correlates in many cases with aphasia, which can occur as a central nervous system-related language disorder, for example, as a result of strokes, tumors, cerebral hemorrhage, inflammation, or intoxication.
Symptoms, complaints, and signs
The main symptom of acalculia is the presence of an acquired impairment in dealing with numbers and other arithmetic quantities. The specific manifestation of this dyscalculia depends primarily on the extent of the neurological disorder present. For example, in some affected individuals, the impairment only becomes apparent during complex arithmetic operations. In other cases, acalculia is manifested by difficulties in dealing with numbers, distances, telephone numbers, times and dates. As a result of the arithmetic impairment, those affected are often unable to handle money, as they cannot correctly estimate price discounts and quantities. Especially if aphasia is present at the same time, there are problems with counting. In addition, auditory comprehension of numbers is often impaired. Affected persons repeatedly make mistakes in reading and writing as well as in the regular arrangement of numbers. They also have difficulties with arithmetic, since the ability to perform operations on numbers is severely impaired in acalculia. Arithmetic signs are often confused or not understood. In severe cases, the ability to do arithmetic is not present at all or is often limited to only a few basic arithmetic operations. The other intelligence of the affected person is not further limited by the disease.
Diagnosis and course
Various screening procedures exist for the detection of acalculia, in which the potentially impaired arithmetic operations can be checked in specific tests. Possible screening procedures are the so-called Number Processing and Calculation Test (ZRT) in combination with a test for cognitive estimation as well as the NPC test (Number Processing and Calculation Battery).In general, the most important representations of numbers and transcoding pathways (e.g., can the Arabic number “26” be assigned to the phonetic sequence “twenty-six”), basic arithmetic operations, as well as counting, approximative calculations, and number sense span are tested in these screening tests. Differential diagnosis should distinguish acalculia from dyscalculia, dementia, and number illiteracy. In addition, to rule out premorbid underachievement, the level of performance prior to the lesion should be considered. In general, the prognosis and course of an acalculia depends on the type and location of the underlying lesion. Although spontaneous courses in acalculia have not been conclusively studied, improvement can generally be assumed after five to six months after the triggering event (including stroke).
Complications
Acquired dyscalculia is not necessarily associated with complications. However, there is usually a serious underlying cause of the memory impairment, such as a stroke or tumor, which can cause further problems. After the triggering incident, many affected persons suffer from persistent attention deficits or have difficulty concentrating. Neurological deficits are often added and the overall quality of life of the affected person decreases. The dyscalculia itself can cause complications if the patient had a lot to do with numbers professionally before the incident. Professions in accounting, for example, can usually no longer be performed with dyscalculia. Even after the acalculia has receded, those affected have to be completely retrained. This represents a great psychological burden, which cannot be overcome without outside help, especially in the case of serious accompanying symptoms. As a rule, no complications occur during therapy. Occasionally, however, sedatives and stimulants are prescribed and these are always associated with side effects. Medications prescribed to treat the causative condition may also cause discomfort and occasionally cause interactions and allergic reactions.
When should you see a doctor?
These days, dyscalculia is noticed during the child’s development and growth process. Guardians and teachers have the responsibility to organize help and medical support in case of irregularities. In some cases, acalculia occurs in an adult. This is preceded by a precipitating event such as a stroke or damage to the brain. Due to the underlying condition, the individual is already receiving medical treatment and should address changes in their computational skills. Help is needed as soon as the understanding of numbers is disturbed. The severity of the irregularity varies among sufferers. Abnormalities may occur in simple or complex arithmetic tasks. A doctor should be consulted for clarification as soon as, in addition to a restriction of academic performance, particularities in everyday life become apparent. In the case of poor handling of money or the inability to estimate distances and quantities, a visit to the doctor is recommended. If clock times cannot be read, understood or put into practice in a meaningful way, this is a cause for concern. Problems with telling dates, assigning house numbers, or using the telephone should result in a visit to the doctor. Repeated errors in reading and writing numbers are another sign of an irregularity. Lack of auditory number comprehension is also needed by a doctor.
Treatment and therapy
Therapy measures in acalculia are aimed at either restitution (recovery) of impaired functions and abilities or reorganization,Therapy measures in acalculia are aimed at either restitution (recovery) of impaired functions and abilities or reorganization, in which other intact cognitive functions are brought to compensatory use. In the context of restitution, the lost knowledge is primarily trained through intensive practice sessions in which the impaired functions, in particular transcoding and recalling the already stored arithmetic knowledge, are trained in order to establish a stable link between the specific arithmetic problem at hand and the correct solution.In this context, it is recommended to take into account exercises specific to everyday life (e.g. reading the time, handling money and calculating change) as well as job-related tasks when reintegrating into working life as a rehabilitation goal. In addition, rehabilitation should begin at the level of difficulty at which the patient shows signs of impairment. Therapy approaches aimed at reorganizing arithmetic competencies are used to teach specific strategies and basic arithmetic rules (e.g., 5 x 6 = (5 x 10) – (5 x 4)) to compensate for the functions affected by acalculia in the context of practice sessions.
Prevention
Acalculia can only be prevented in a restrictive manner. For example, as part of arteriosclerosis prophylaxis, the risk of stroke and thus possible acalculia can be reduced.
Follow-up
In the case of dyscalculia or acalculia, aftercare aims to consolidate the newly learned sense of numbers and of mathematical processes. In doing so, unlearning of these skills and a recurrence of the dyscalculia are prevented. The sooner the learning disability is diagnosed, the better the chances of recovery. The psychological aspect of dyscalculia is no less important: children with acalculia often suffer from school anxiety or psychosomatic complaints such as nausea before starting school or anxiety during math lessons. Self-confidence can be affected if there is no success despite repeated arithmetic exercises. If classmates experience the child’s learning difficulties in class, the risk of bullying is also very high. If one or more of these situations occur, a psychologist must be consulted in order to counteract permanent damage to the child’s self-esteem. Ways are worked out together with the child in the therapy sessions to consolidate self-confidence.
What you can do yourself
In order to gradually restore the ability to calculate in acalculia in the best possible way, intensive training is necessary. The degree of difficulty must be determined individually by a doctor and gradually increases. The most suitable exercises are those that are adapted to the everyday life of the affected person. These include reading the time and calculating with money. Later, more difficult relationships can be introduced. In the case of severe dyscalculia, it is a good start to first integrate simple arithmetic rules into everyday life. Special learning materials for dyscalculia can be used for this purpose. Textbooks are another option. Group training with other sufferers is also recommended. If this is not possible, non-ill relatives can also help the ill person. They can support the sufferer individually. For example, they can practice mental arithmetic or writing down longer numbers. Depending on the severity of the dyscalculia, support in everyday situations is also necessary. Since acalculia is often the result of a disorder of the left hemisphere of the brain, it is advisable to train this hemisphere specifically. Not only arithmetic tasks, but also language exercises as well as other mental exercises can be used for this purpose.
